Throughout this application various publications, patents, patent application publications and books are referred to. Full citations for the publications may be found at the end of the specification. The disclosures of the publications, patents, patent application publications and books are hereby incorporated by reference in their entirety into the subject application to more fully describe the art to which the subject invention pertains.
Poor immunogenicity of conventional protein vaccines, in particular an inability to elicit robust T cell-mediated immunity, has limited their use as vaccines targeting diverse diseases including viral infections and cancers. One approach, which has recently been utilized to activate T cell responses, is targeting of antigen to dendritic cells (DCs), a cell type that is pivotal for eliciting T cell activation. Indeed, DC-targeted approaches have recently attracted significant research interest and are rapidly becoming important therapeutic approaches (1-4). DCs possess the capability of processing self and foreign antigens resulting in presentation of antigen to its cognate T cell receptor. Targeting antigen uptake to DCs via specific DC-enriched receptors has been shown to enhance antigen presentation on major histocompatibility complex (MHC) class I and II molecules by as much as 1000-fold and 50-fold, respectively (5). Depending on the antigenic stimulus, DCs can induce tolerance or activate the immune system (6), making them important targets in the development of novel treatments to autoimmune diseases, viral infections and cancer. Targeting antigens to DCs most often involves coupling the antigen of interest to a delivery agent specific for a readily endocytosed cell surface receptor on the DCs.
Typically, targeted antigen delivery has made use of antibodies as the targeting agent. However, large size and immunogenicity have presented problems in this approach.
The present invention addresses the need to providing improved targeting methods by providing aptamers for preferential vaccine targeting.